1. Field of the Invention
The invention is directed to a feed device comprising filling hopper and adjoining feed chute, feeding pistons being provided at the lower end of the latter for conveying waste to an incineration plant.
2. Background Prior Art
Waste is an extremely heterogeneous combustible material which differs in composition, so that difficulties can occur when charging incineration plants. The difficulties are based on the fact that the waste, depending on its composition, slides easily in one instance and accordingly has the tendency to slide into the incineration plant from the filling hopper, but, in another composition, is bulkier and does not have a good sliding behavior. In spite of the fact that the manner of operation of the feeding pistons remains constant, this leads to different feed quantities which, in connection with the different thermal values of the waste, can lead to a sharply fluctuating release of heat and accordingly to a fluctuating thermal output of the incineration plant.
A primary object of the invention is to construct the feed device of the type described above in such a way that the waste is prevented from sliding through over the feeding pistons and a uniform feeding of the waste into the incineration plant is ensured.
This object is met by a feed device comprising a filling hopper and adjoining feed chute. Feeding pistons are provided at the lower end of the feed chute for conveying waste to an incineration plant. An arrangement of at least one retaining and compression body on at least one feeding piston prevents the waste quantity fed into the filling hopper from sliding away over the feeding pistons in an uncontrolled manner. In addition to this retaining function, it is also achieved that the waste is somewhat compressed by means of this retaining and compression body during the return stroke of the feeding pistons, so that a compression of the waste is achieved particularly when the waste is very loose, so that the density of the combustible material is increased and an improved metering of this pre-compressed waste is made possible by means of the next forward stroke of the feeding piston.
The retaining and compression bodies can be provided in the area of the front ends of the feeding pistons or directly at the front end of the feeding pistons. A plurality of retaining and compression bodies, which can either be arranged adjacent to one another or so as to be offset relative to one another, can be arranged on every feeding piston. However, it is also possible that the retaining and compression body of a feeding piston is constructed as a body extending along the entire width of the feeding piston.
The retaining and compression bodies of adjacent feeding pistons can be offset relative to one another or aligned with one another.
Different shapes of the retaining and compression bodies can be advantageous depending on the composition of the waste and as a function of the angle at which the waste mass flow moves on the feeding piston.
In a determined combination of these preconditions, a first advantageous construction for achieving the retaining and compression effect can consist in that the retaining and compression bodies comprise a steeply dropping flank toward the rear end of the feeding piston and a gradually dropping flank toward the front end of the feeding piston. Accordingly, it is achieved that the driving or entraining effect of these bodies on the loose waste lying on the feeding piston during the forward stroke of the feeding piston is less than the retaining and compression effect during the reverse stroke of the feeding piston.
In another combination of the preconditions mentioned above, it can be advantageous, according to another construction of the invention, if the retaining and compression bodies comprise a gradually dropping flank toward the rear end of the feeding piston and a steeply dropping flank toward the front edge of the feeding piston.
The retaining and compression bodies can be constructed as flat bodies arranged on edge having an outline which is rectangular, trapezoidal, triangular or arc-shaped as seen from the side. However, the retaining and compression bodies can also be shape in the manner of a pyramid, a pyramid frustum, a cone, cone frustum or a spherical shell.
The invention is explained in more detail in the following with the aid of the embodiment examples shown in the drawing in a schematic manner. The scope of the invention will be pointed out in the appended claims.